System and method for navigating an instrument

ABSTRACT

Disclosed is an instrument assembly usable in a procedure. The instrument includes a connection for a working portion and to a tool handle. A tracking device or assembly may be associated with the instrument for determining a position of the instrument.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application includes subject matter related to that disclosed inU.S. patent application Ser. No. 16/055,747 and U.S. patent applicationSer. No. 16/055,782. The entire disclosures of the above applicationsare incorporated herein by reference.

FIELD

Disclosed is a system for tracking an instrument, and particularly asystem and method to track an instrument during a procedure with arotating tool.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

A surgical instrument may be used during a procedure such as within aselected region of a subject's anatomy. The surgical instrument may beout of view of a user, such as below a tissue of a subject during aprocedure. A user, therefore, may be required to remove an instrument toview the exact location of the instrument or the condition of a surgicalsite. Accordingly, a procedure may require intermittent application of aselected surgical instrument, such as a burr.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

A driver may power an instrument, such as a burr or other resection ordriven instrument during a selected procedure. The instrument may beremovably connected to a driver, such as a powered tool handle. Thepowered tool handle may include a motor and a portion that is graspableby a user, such as surgeon.

In using the instrument during the procedure, the user may desire orselect to navigate the instrument. In navigating the instrument, atracked location of at least a portion of the instrument is determined.In tracking the instrument, a navigation system may determine andillustrate a position of the instrument relative to an image of thesubject or patient for a selected period of time.

The tracking device may include selected portions that areinterconnected or formed with the instrument. The instrument may includea working end, an elongated shaft, and a hub or connection portion toconnect to the tool handle. The hub portion may incorporate variousportions, such as the tracking device.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is an environmental view of an operating theater with a trackingsystem;

FIG. 2 is a perspective view of a tool and instrument, according tovarious embodiments;

FIG. 3 is a detailed view of an instrument with a tracking device,according to various embodiments;

FIGS. 4A-4C are different plan views of an instrument hub and connectorrotated around a long axis of the hub, according to various embodiments;and

FIG. 4D is a detail view of a hub.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

With initial reference to FIG. 1, in a procedure a navigation system 10may be used by a user 12 to perform a selected procedure. The navigationsystem 10 may include various components that assist in navigating aprocedure including a selected tracking system. The tracking system mayinclude various components or portions such as various localizers.Various localizers may include an optical tracking system and/or anelectromagnetic tracking system that includes a Tracking Coil Array(TCA) localizer 14. While the optical tracking system may be used inconjunction with or simultaneously with the TCA 14, it is understoodthat only one tracking system may be used with the navigation system 10.In various embodiments, therefore, both an optical localizer 82 and theTCA 14 may be used together or simultaneously for tracking one or moreinstrument, or only one. An instrument 16 may be tracked during aselected procedure, such as a navigated procedure with the navigationsystem 10.

The TCA 14 may include one or more conductive coils 18 positionedrelative to a subject 20 on which a procedure is performed. In variousembodiments, a procedure may be performed on or near a head 20 h of thesubject 20. As discussed in further detail herein, a subject trackingdevice or assembly 30 may be connected to the subject 20, such as to thehead 20 h of the subject 20. The tracking assembly 30 may also bereferred to as a Dynamic Reference Frame (DRF) or a patient tracker.

With continuing reference to FIG. 1, the navigation system 10 mayinclude various features or elements as discussed below. Generally, thenavigation system 10 may be used to determine or track a position of aninstrument 16 in a volume. The position may include both a threedimensional X,Y,Z location and orientation. Orientation may include oneor more degrees of freedom, such as three degrees of freedom. Thus, atotal of at least six degrees of freedom may be determined for theposition of the instrument 16.

Tracking the position of the instrument 16 may assist the user 12 indetermining a position of the instrument 16, even if the instrument 16is not directly viewable by the user 12. Various procedures may blockthe view of the user 12, such as performing a repair or assembling aninanimate system, such as a robotic system, assembling portions of anairframe or an automobile, or the like. Various other procedures mayinclude a surgical procedure, such as performing a spinal procedure,neurological procedure, positioning a deep brain simulation probe, orother surgical procedures on a living subject. In various embodiments,for example, the living subject may be a human subject 20 and theprocedure may be performed on the human subject 20. It is understood,however, that the instrument 16 may be tracked and/or navigated relativeto any subject for any appropriate procedure. Tracking or navigating aninstrument for a procedure, such as a surgical procedure, on a human orliving subject is merely exemplary.

Nevertheless, in various embodiments, the surgical navigation system 10,as discussed further herein, may incorporate various portions orsystems, such as those disclosed in U.S. Pat. Nos. RE44,385; 7,697,972;8,644,907; and 8,842,893; and U.S. Pat. App. Pub. Nos. 2004/0199072, allincorporated herein by reference. Various components that may be usedwith or as a component of the surgical navigation system 10 may includean imaging system 34 that is operable to image the subject 20, such asan O-arm® imaging system, magnetic resonance imaging (MRI) system,computed tomography system, etc. A subject support 36 may be used tosupport or hold the subject 20 during imaging and/or during a procedure.The same or different supports may be used for different portions of aprocedure.

Image data may be acquired during a surgical procedure or acquired priorto a surgical procedure for displaying an image 38 on a display device39. The instrument 16 may be tracked in a trackable volume or anavigational volume that is produced by the transmitter antenna ortransmitting coil array 18 that is incorporated into the localizer 14,as illustrated in FIG. 1. The position of the instrument 16 may betracked in the tracking volume relative to the subject 20 and thenillustrated as an icon 16 i with the display device 39. In variousembodiments, the icon 16 i may be superimposed on the image 38 and/oradjacent to the image 38. As discussed herein, the navigation system 10may incorporate the display device 39 and operate to render and displaythe image 38, from image data. Also, the determined the position of theinstrument 16 may be performed and displayed with the display device 39,such as the icon 16 i.

With reference to FIG. 1, the localizer 14 may be an electro-magnetic(EM) localizer that is operable to generate electro-magnetic fields withcoils 18 of the transmitting coil array (TCA) 14 which is incorporatedinto the localizer 14. The TCA 14 may include one or more coil groupingsor arrays. In various embodiments, more than one group is included andeach of the groupings may include three coils, also referred to as triosor triplets. The coils may be powered to generate or form anelectro-magnetic field by driving current through the coils of the coilgroupings. As the current is driven through the coils, theelectro-magnetic fields generated will extend away from the coils 18 andform a navigation domain or volume 50, such as encompassing all or aportion of a head 20 h, spinal vertebrae, or other appropriate portion.The coils 18 may be powered through a TCA controller and/or power supply52.

The navigation domain or volume 50 generally defines a navigation spaceor patient space. As is generally understood in the art, the instrument16, such as a drill, lead, etc., may be tracked in the navigation domainrelative to a patient or subject with an instrument tracking device 56.For example, the instrument 16 may be freely moveable, such as by theuser 12, relative to the DRF 30 that is fixed relative to the subject20. Both the tracking devices 30, 56 may include tracking or sensingcoils (e.g. conductive material formed or placed in a coil) that sensesand are used to measure a magnetic field strength, etc. Due to thetracking device 56 connected or associated with the instrument 16,relative to the DRF 30, the navigation system 10 may be used todetermine the position of the instrument 16 relative to the DRF 30.

The navigation volume or patient space may be registered to an imagespace of the patient and the icon 16 i representing the instrument 16may be illustrated at a navigated (e.g. determined) and tracked positionwith the display device 39, such as superimposed on the image 38.Registration of the patient space to the image space and determining aposition of a tracking device, such as with the tracking device 56,relative to a DRF, such as the DRF 30 may be performed as generallyknown in the art, including as disclosed in U.S. Pat. Nos. RE44,385;7,697,972; 8,644,907; and 8,842,893; and U.S. Pat. App. Pub. Nos.2004/0199072, all incorporated herein by reference.

The navigation system 10 may further include a navigation processorsystem 66. The navigation processor system 66 may include the displaydevice 39, the localizer 14, the TCA controller 52, and other portionsand/or connections thereto. For example, a wire connection may beprovided between the TCA controller 52 and a navigation processing unit70. Further, the navigation processor system 66 may have one or moreuser control inputs, such as a keyboard 69, and/or have additionalinputs such as from communication with one or more memory systems 72,either integrated or via a communication system. The navigationprocessor system 66, according to various embodiments, may include thosedisclosed in U.S. Pat. Nos. RE44,385; 7,697,972; 8,644,907; and8,842,893; and U.S. Pat. App. Pub. Nos. 2004/0199072, all incorporatedherein by reference, and/or may also include the commercially availableStealthStation® or Fusion™ surgical navigation systems sold by MedtronicNavigation, Inc. having a place of business in Louisville, Colo.

Tracking information, including regarding the magnetic fields sensedwith the tracking devices 30, 56, may be delivered via a communicationsystem, such as the TCA controller 52, which also may be a trackingdevice controller 52, to the navigation processor system 66 includingthe navigation processor 70. Thus, the tracked position of theinstrument 16 may be illustrated as the icon 16 i relative to the image38. Various other memory and processing systems may also be providedwith and/or in communication with the processor system 66, including thememory system 72 that is in communication with the navigation processor70 and/or an imaging processing unit 76. The image processing unit 76may be incorporated into the imaging system 34, such as the O-arm®imaging system, as discussed above. The imaging system 34 may,therefore, include various portions such as a source and a x-raydetector that are moveable within a gantry 78. The imaging system 34 mayalso be tracked with a tracking device 80. It is understood, however,that the imaging system 34 need not be present while tracking thetracking devices, including the instrument tracking device 56. Also, theimaging system 34 may be any appropriate imaging system including a MRI,CT, etc. In various embodiments, the localizer may also include anoptical camera system 82. The optical camera system 82 may be used inconjunction with or alternatively to the localizer 14 for tracking theinstrument 16.

Information from all of the tracking devices may be communicated to thenavigation processor 70 for determining a position of the trackedportions relative to each other and/or for localizing the instrument 16relative to the image 38. The imaging system 34 may be used to acquireimage data to generate or produce the image 38 of the subject 20. It isunderstood, however, that other appropriate imaging systems may also beused. The TCA controller 52 may be used to operate and power the TCA 14,as discussed above.

With continuing reference to FIG. 1 and additional reference to FIGS.2-4D, the instrument 16 may include various portions such as a distal orworking end 100. The working end 100 may be formed as a selectedinstrument working end or portion, such as a burr, grinder, cutter, orcutting tool that is rotated by a motor 104 within a handle or toolhandle 106. The tool handle 106 may be held with a single hand of theuser 12 and be operated by the user 12. In various embodiments, a footswitch is provided to power on and off the motor 104 while the userholds the handle 106. The instrument 16 may further include an elongatedtube or shaft 110. The elongated tube 110 may include an internal and/orexternal portion, such as the tools sold with the StraightShot® M5 powerhandle, by Medtronic, Inc., having a place of business in Minneapolis,Minn. In various embodiments, the shaft 110, may be included as anelongated tube or a tubular shaft.

The instrument 16, including the elongated tube 110, may include anexterior wall having an interior cannula through which the working end100 is powered, such as by an elongated shaft 101 to drive the workingend 100. As discussed further herein, the shaft 101 driving the workingend 100 may connect with the motor 104 through a hub 120. The hub 120may engage a collet 124 to hold or fix the instrument 16 relative to thehandle 106.

In various embodiments, irrigation may be provided through theinstrument 16, such as through or by an irrigation barb 226. It isunderstood that the irrigation barb 226 may be connected with anirrigation hose or tubing to provide irrigation through the instrument16. Further, suction may be drawn or pulled through the instrument 16,and through the handle 106, such as through a suction tube 130. Thesuction tube 130 and an electrical connection line 132 may be connectedto a console or controller, which may be incorporated with the TCAcontroller 52. It is understood that the console or controller may besimilar to the console Medtronic IPC® power and control console orSystem, sold by Medtronic, Inc. Nevertheless the instrument 16 may bemoved and powered by the handle 106 when operated by the user 12.

In various embodiments, the tracking device 56 may be incorporated intoor onto the hub 120. With exemplary reference to FIG. 3-4C, the trackingdevice 56 may be incorporated onto the hub 120 of the instrument 16. Thehub 120 of the instrument 16, as illustrated in FIG. 3, may be connectedto the shaft 110 through which the shaft 101 of the bit or working end100 passes. The shaft 101 extends through the hub 120 and may terminateand/or engage a tongue 140. The tongue 140 may terminate and/or have aterminal end 142. The terminal end 142 may have a keyed or engagingportion, such as an engaging wall 144 to engage an internal element inthe handle 106. For example, a shaft extending from the motor 104 mayengage the engaging wall 144 of the tongue 140. An interference betweenthe shaft extending from the motor 104 and the engaging wall 144 mayallow for transfer of forces from the motor 104 to the tongue 140. Asthe tongue 140 is connected to the bit shaft 101, the working end 100may then rotate due to a force transferred through the tongue 140. Theshaft 101, passing through the hub 120, may allow for the hub 120 to bepositioned or moveable relative to the handle 106 and carry variouscomponents, such as the tracking device 56 relative thereto.

Generally, the bit shaft 101, working end 100, tongue 140, and hub 120components are provided as a single assembly, such as from a supplier.Thus, the user 12 may connected the instrument 16 to the handle 106,including the motor 104, as a single action or assembly. Further, theinstrument may be a single use or one time use instrument. This allowsthe instrument to be useable with the handle 106 for the procedure,including tracking of the instrument 16, while allowing ease or assemblyand efficient sterile preparation and disposal.

The hub 120 is illustrated in greater detail in FIGS. 4A, 4B, and 4C anddiscussed below. A detail view of the hub 120 is illustrated in FIG. 4D.Initially, the working end 100 and the associated shaft 101 may beformed of a selected material, such as a metal or metal alloy. Invarious embodiments, the shaft 110 of the instrument 16 may also beformed of a selected metal or metal alloy material. The hub 120 may beformed as a single member either with the shaft 110 or separatetherefrom. For example, the hub 120 may be formed of a selected polymermaterial that may be over molded or injection molded onto the shaft 110.It is understood, however, that the hub 120 may be formed separatelyfrom the shaft 110 and connected during assembly of the instrument 16.Moreover, it is understood that the hub 120 may be formed of selectedappropriate materials such as polymers, co-polymers, metal alloys,selected bearing materials, combinations thereof, or the like.

The hub 120 generally extends from a proximal end 150 to a distal end152. The proximal end 150 and distal end 152 may further be terminalends of the hub 120. As illustrated in FIG. 3, and discussed furtherherein, at least a portion of a distal portion, such as extending fromthe distal end 152 toward the proximal end 150, may be a covering orencapsulation 154. The encapsulation portion or member 154 may include awrapping or shrink wrap formed over selected portions of the hub 120, asdiscussed further herein. It is further understood that the cover 154may a rigid member that is passed on to the hub 120, such as over theshaft 110. The tracking device 56, even when covered, may have anexternal dimension (e.g. cross-sectional diameter) 56 a that is lessthan or equal to an external dimension 106 a of a portion of the handlenear or adjacent to the hub 120 and/or external dimension 106 a′ of achuck or instrument attachment. Thus, the hub 120 including the trackingdevice 56 may allow a large field of view and efficient operation of theinstrument 16 and the handle 106.

For example, positioned on and/or fixed to the hub 120 may be aplurality of tracking elements or members that form the tracking device56. The tracking elements may include a first tracking coil assembly160, a second tracking coil assembly 162, and a third tracking member164. Each of the tracking members 160, 162, 164 may incorporate or forma portion of the tracking device 56. For example, each of the memberportions 160, 162, 164 may include a coil, such as a micro coil 166,168, 170, respectively. The coils 166-170 may be formed around an innercore or a magnetically permeable core and positioned relative to acontact member or support. The coils 166-170 may be formed of a selectedwire or connective material of a selected diameter. For example, thecoils are formed by winding around an air core or selected core and inselected ends. Each of the coils 166-170 may be placed or connected to aboard, such as a printed circuit board 174, 176, 178, respectively. Theends of the coils 166-170 may be mounted or fixed to selected conductiveportions of the respective boards 174-178.

With reference to FIG. 4D, the coil assembly 162 is illustrated ingreater detail. The hub 120 may include various mounting or fittingportions. For example, a well or holding region 167 may be defined bywalls. An end wall 169 a, a proximal wall 169 b, and one or more sidewalls 169 c, 169 d may extend from a surface of the hub 120. The walls169 may form or define the well to receive or hold the coil assembly 162in a selected position, including location and orientation relative tothe hub 120. The well may assist in manufacturing such as that the coilassembly 162 is positioned in a selected and appropriate position foreach hub 120. Further, each of the coil assemblies may be placed insimilar wells.

The coil 168 may include ends of the coiled wire that are mounted to theboard 176, such as to pads. The board 176 may include traces toadditional pads 173, 175. The pads 173, 175 on the board 176 allow for aconnection, such as an efficient and repeatable connection, of theconnector 188. Again, one skilled in the art will understand that eachcoil assembly may include a similar assembly.

The coil and board assemblies may then be fixed to the hub 120 in aselected manner. For example, the coils may be respectively epoxied oradhered to the respective boards 174-178. The epoxied assemblies may beadhered or epoxied to the hub 120, such as into the well or pockets 167.Generally, the member portions 160, 162, 164 generally have similar oridentical dimensions and a generally rectangular shape having dimensionsof about 2 millimeters (mm) to about 6 millimeters per side, wheremeasurements may include a measurement and/or manufacturing tolerance ofabout 0.01 mm to about 2 mm. Exemplary dimensions may include about 5 mmby about 3 mm, about 3 mm by about 2 mm, about 3.05 mm by 3.81 mm, andabout 2.54 mm by about 5.33 mm. Generally, the member portions may havean area of about 13 mm², including less than about 20 mm², less thanabout 15 mm² and about less than about 8 mm².

Further, a connector or communication line 184 may have selected twistedpair wires leads for each of the boards, such as a first lead 186, asecond lead 188, and a third lead 190. Each of the respective leads186-190 may also be fixed to the respective boards 174-178. It isunderstood that the respective leads 186-190 and the terminal ends ofthe coils 166-170 may be soldered or selectively affixed to therespective boards 174-178, as is generally understood in the art.

The leads may pass along the common connector line 184 to a proximalconnector 196. The connector 196 may include a physical connection 198to a selected console or assembly, such as the TCA controller 52. Asdiscussed herein navigation or tracking information from the trackingdevice 56 may be transmitted along the common connector 184 to theconnector 196 and the physical connection 198.

In the connector 196, in various embodiments, the physical connector 198may include a selected memory and/or processor assembly 200. The memoryand/or processor assembly 200 may include information regarding theinstrument 16 to which the hub 120 is affixed. Information may include ageometry, such as a geometric position of the working end relative tothe tracking device. For example, the information may include a distance210, along an axis 214 of the instrument 16, from the tracking devicemay be the information. In addition and/or alternatively thereto, theinformation may include an offset distance 212 from the axis 214 of theinstrument 16 to a working terminal end plane or position 216 of theworking end 100.

Accordingly, the memory and/or processor assembly 200 may havecalibrated a predetermined or known positions of the working end 100relative to the tracking device 56 stored thereon. The storedinformation may be transferred to the navigation system 10 when thephysical plug 198 has attached to the TCA controller 52. In transmittingthe information, such as with a signal from the memory and/or processorassembly 200 to the navigation processor system 66, the processor system66 is able to access or determine the calibrated position of the workingend 100 relative to the tracking device 56.

The hub 120 may further include other components such as a fixationportion or member 220 to assist in holding the single line 184 relativeto the hub 120. The fixation 220 may be a selected adhesive, wrapping,insulation wrapping, or the like. Further the hub 120 may includeselected connection features, such as keyed or non-cylindrical features222 which may include interference walls or facets. Further, the hub 120may include an irrigation line connection, such as hose barb 226 toallow for a connection of an irrigation line to the hub 120. In variousembodiments, the irrigation line may be connected to the barb 226 toprovide a delivery of fluid through the hub 120 and thereafter throughthe shaft 110 around the working end 100. A suction may also be providedthrough a second inner cannula due to the suction line 130, as discussedabove.

To assist in tracking the instrument 16, or portions thereof, thetracking device 56 includes the tracking members 160, 162, 164 that areselectively positioned on the hub 120. For example, each of therespective coils 166-170 may be positioned at about 100 to about 150degrees, including about 120 or exactly 120 degrees, around the axis 214relative to one another. It is understood that the tracking members160-164 may be selectively positioned for various purposes.

Each of the respective coils 166-170 may be orthogonally positionedrelative to one another. The field generated by the TCA 14 may then besensed by the coils 166-170 positioned on the hub 120. That is the firstcoil 166 may sense a field that has a main axis that is substantiallyperpendicular to field sensed by the second coil 166 and the third coil170. To sense the field in the selected orientations, the respectivecoils 166-170 may be positioned on the respective boards 174-178 in aselected manner or each of them may be formed connectively andpositioned at different orientations on the hub 120. It is understood,by one skilled in the art, that the coils 166-170 may also generaterespective fields (e.g. orthogonal to one another) that are sensed bythe TCA 14 for tracking of the tracking device 56.

During use of the navigation system 10, such as when the user 12 ismoving an instrument 16 relative to the subject 20, the tracking device56 may sense the field generated by the TCA 14. As discussed above thesensed field may be used to determine a position of the instrument 16,such as a position of the working end 100, relative to the subject 20.In various embodiments, the DRF 30 may be used in combination with thetracking device 56 to determine the relative position of the instrument16 relative to the subject 20. Accordingly, as discussed above, the icon16 i may be illustrated on the display device 39 to illustrate theposition of the instrument 16 relative to the subject 20.

In having the tracking members 160-164 positioned at the respectivelocations on the hub 120, such as orientated orthogonally to oneanother, a selected degrees of freedom may be determined regarding theposition of the tracking device 56. For example, six degrees of freedommay be determined including a three dimensional (e.g. x,y,z location)and orientation (e.g. three degrees of freedom). It is understood,however, that less than three of the tracking members may be used withthe tracking device 56. Thus, as the motor 104 powers (e.g. rotates) theshaft 101 of the instrument 16, the position of the working end 100 maybe determined and illustrated as the icon 16 i. During operation of theinstrument 16 (e.g. rotating and resecting) and moving the instrument 16(e.g. toward and away from a surface) tracking of the tracking device 56occurs.

Further, the dimension or position of the working end 100 relative tothe tracking device 56 may be recalibrated or determined during aprocedure. For example, the user 12 may position the working end 100relative to the DRF 30 at a selected or known position. The navigationsystem 10 may then calibrate or determine the position of the workingend 100 relative to the tracking device 56 by determining or trackingthe DRF 30 and the tracking device 56. The instrument 16 may then beconnected to the handle 106, if not already connected, and thenavigation may proceed without a predetermined calibration or pre-knownposition of the working end 100 relative to the tracking device 56.

Example embodiments are provided so that this disclosure will bethorough, and will fully convey the scope to those who are skilled inthe art. Numerous specific details are set forth such as examples ofspecific components, devices, and methods, to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to those skilled in the art that specific details need not beemployed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. A system for determining a position of a workingend of a driven instrument, comprising: an elongated tubular memberhaving a cannula therein; a hub extending along a longitudinal axis andconnected to the elongated tubular member; and a tracking deviceconnected to the hub having at least one tracking member; wherein thehub is configured to be connected to a tool motor handle having a toolmotor to drive a shaft and the tracking device has an externalcross-sectional dimension transverse to the longitudinal axis of the hubless than at least an external cross-sectional dimension transverse tothe longitudinal axis of a distal end of the tool motor handle; whereinan external surface of the hub defines a plurality of rectangular-shapedwells formed into the external surface; and wherein the tracking deviceincludes a plurality of tracking devices, one of each of the pluralityof tracking devices positioned in a corresponding one of eachrectangular-shaped well formed in the hub.
 2. The system of claim 1,further comprising: the shaft positioned and extending through thecannula; and the working end attached to the shaft and extending fromthe elongated tubular member to be driven by the shaft.
 3. The system ofclaim 2, wherein the shaft extends through the hub.
 4. The system ofclaim 3, further comprising: the tool motor handle; wherein theelongated tubular member, the hub, the tracking device, the shaft, andthe working end are configured as an assembly and attached to the toolmotor handle as a single unit.
 5. The system of claim 1, wherein the hubincludes a plurality of straight walls extending from the externalsurface to form the plurality of rectangular shaped wells in a surfaceof the hub.
 6. The system of claim 5, wherein each of the trackingdevices includes a coil of conductive material formed around a core andcarried by a printed circuit board to form a tracking coil assemblyhaving a rectangular shape; wherein the conductive material is connectedto the printed circuit board; wherein a rectangular shaped tracking coilassembly is received in each rectangular shaped well.
 7. The system ofclaim 2, wherein the working end includes a burr, a rotating cutter, agrinder, or combinations thereof.
 8. The system of claim 1, furthercomprising: a connector electrically connected to the tracking device;wherein the connector includes a memory having calibration informationregarding the drive instrument.
 9. The system of claim 1, wherein eachof the plurality of tracking devices includes a coil coupled to aprinted circuit board and each coil and printed circuit board forms atracking coil assembly rectangular-shaped positioned in each well.
 10. Asystem for determining a position of a working end of a driveninstrument, comprising: an instrument assembly, including: an elongatedtubular member having a cannula therein; a working tool having a shaftextending through the cannula and a working end attached to the shaft,wherein the working end extends from the elongated tubular member andconfigured to be driven by the shaft; a hub fixedly connected to theelongated tubular member, wherein the shaft extends through the hub; anda tracking device connected to the hub, wherein the tracking deviceincludes at least one tracking member; and a tracking system configuredto track a position of the tracking device; wherein the hub isconfigured to be connected to a tool motor to drive the shaft; whereinthe hub has an external surface that defines a rectangular-shaped wellformed within the external surface; and wherein the tracking devicehaving the at least one tracking member includes a coil attached to aprinted circuit board to form a rectangular-shaped tracking coilassembly having a surface area less than the about 20 squaremillimeters; wherein the rectangular-shaped tracking coil assemblyhaving the coil and the printed circuit board is received in therectangular-shaped well formed in the external surface of the hub. 11.The system of claim 10, further comprising: the tool motor having ahandle and a motor; wherein the working tool is rotated by the motorwhile the tracking system tracks the tracking device.
 12. The system ofclaim 11, wherein an external cross-sectional dimension transverse to alongitudinal axis of the hub and tracking device is less than anexternal cross-sectional dimension transverse to a longitudinal axis ofthe handle adjacent to the hub.
 13. The system of claim 10, wherein thetracking device is adhered to the external surface of the hub.
 14. Thesystem of claim 13, wherein the hub includes a plurality ofrectangular-shaped wells forming walls extending from the externalsurface; wherein the tracking device is adhered to the external surfaceof the hub within a well defined by the plurality of well forming walls.15. A system to track an instrument, comprising: a hub extending alongan axis and having an exterior surface, the exterior surface defining arectangular-shaped recessed well therein; a tubular member connected tothe hub; an instrument shaft extending through the tubular member andthe hub; and a tracking member affixed within the rectangular-shapedrecessed well within the exterior surface of a wall of the hub, thetracking member having a coil affixed to a printed circuit board to forma rectangular-shaped tracking coil assembly; wherein the hub isconfigured to be fixed to a power tool handle.
 16. The system of claim15, wherein the tracking member is configured to track a position of aworking end connected to the instrument shaft while the instrument shaftrotates.
 17. The system of claim 16, wherein the tracking member affixedto the hub defines an external cross-sectional dimension transverse tothe axis less than an external cross-sectional dimension transverse to alongitudinal axis of the power tool handle.
 18. The system of claim 15,further comprising: the power tool handle, wherein the power tool handleincludes a motor configured to selectively rotate the instrument shaft.19. The system of claim 18, wherein the power tool handle is operable tobe manipulated by a single hand of a user to perform a procedure.